I know this question might seem like a duplicate question, but I think its not. I'm trying to install java 8 on my ubuntu 14.04 LTS. I have tried many methods, but nothing worked for me. So I downloaded jre-8u25-linux-x64.tar.gz. Then I did the following:

tar -xvf jre-8u25-linux-x64.tar.gz 
sudo mkdir -p /usr/lib/jvm
sudo mv ./jdk1.8.0_25/ /usr/lib/jvm
sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.8.0/bin/java" 1

but I got the following error :

update-alternatives: error: alternative path /usr/lib/jvm/jdk/bin/java doesn't exist`

When I opened jdk1.8.0_25 I didn't find bin/java in it, so I re-downloaded it, but the same problem occurred.

Can anyone tell me what I'm doing wrong here?

EDIT:

The output of : update-alternatives --display java

update-alternatives: warning: alternative /opt/jdk/jdk1.8.0_05/bin/java (part of link group java) doesn't exist; removing from list of alternatives
java - auto mode
  link currently points to /usr/lib/jvm/java-7-oracle/jre/bin/java
/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java - priority 1071
  slave java.1.gz: /usr/lib/jvm/java-7-openjdk-amd64/jre/man/man1/java.1.gz
/usr/lib/jvm/java-7-oracle/jre/bin/java - priority 1072
  slave java.1.gz: /usr/lib/jvm/java-7-oracle/man/man1/java.1.gz
Current 'best' version is '/usr/lib/jvm/java-7-oracle/jre/bin/java'.